1. Field of the Invention
The present invention relates to an electrical connector and a method of assembling discrete wires in a predetermined arrangement within an electrical connector housing. This invention also relates to a shielded electrical arrangement and a method for making the same.
2. Brief Description of the Prior Art
It is very common to mass terminate a plurality of insulated conductors to a connector. The conductors may be provided for mass termination in a variety of forms. In round conductor ribbon cable, for example, discrete wire conductors are disposed in parallel spaced relation to each other between insulating dielectric layers which surround and insulate the wires and form webs of insulation between them. Alternatively, conductors may be provided in the form of a multi-cable assembly plurality of insulated conductors surrounded by an outer insulation jacket of a generally round cross section. This latter type of cable assembly presents problems that are absent when dealing with round conductor ribbon cable. When using a ribbon cable, the intervening webs serve to maintain the relative position and spacing of adjacent conductors. On the other hand, when handling discrete wire, the insulated conductors must first be unravelled from a bundle of wires and thereafter positioned in such a manner to permit mass termination with a plurality of terminals.
One means of connecting the discrete wires of a multi-conductor cable assembly to a plug assembly is disclosed in U.S. Pat. No. 4,601,530. In that patent, the plug assembly includes an insulated housing which has a front mating end and a rear wire receiving end which join opposing top and bottom walls. The housing includes a generally planar trough extending from a wire receiving opening in the rear end towards the front end of the housing and a plurality of terminal receiving cavities extending from the top wall into the trough near the front end thereof. Insulative wire positioning means is provided to be received in the wire receiving opening into the trough to hold the insulated conductors in a generally planar array so that the ends thereof are presented in alignment below the terminal receiving cavities when the positioning means is in the housing trough. A plurality of insulation penetrating terminals are mounted in the terminal receiving cavities and movable toward the trough to engage the conductors aligned thereunder. The wire positioning means disclosed in U.S. Pat. No. 4,601,530 is a comb-like wire holder with a series of staggered wire locating apertures. The reason why the apertures must be staggered is that the upstanding resilient fingers separating adjacent apertures take up too much space to allow all of the insulated conductors to be in the same plane.
In the above cited arrangement, it is is essential that the end of a particular conductor not extend past the wire holder structure too far or too little. Otherwise, it is possible that the conductor will not be properly terminated. Thus, the wire positioning structure of U.S. Pat. No. 4,601,530 provides that the apertures be large enough to allow the wires to have a sliding fit therein. Once the structure is received within the plug housing prior to termination, the wires are still axially and slidably movable. This permits last moment realignment prior to termination, but also permits inadvertent misalignment because the wires are not positively held in position. This is particularly important where the plug assembly is to be assembled by a customer in a production environment.
The same drawbacks are apparent in the wire positioning means which is disclosed in U.S. Pat. No. 4,577,920. The plug assembly described in this patent includes a shielded connector assembly which positions a multi-conductor shielded cable assembly within a plug housing. Once again, the conductors are not positively held in position to prevent misalignment prior to termination.
U.S. Pat. No. 4,516,822 discloses a connector assembly which positively positions the wires prior to termination. However, the wire positioning structure comprises two small separate component parts. This is undesireable because of the inherent dual deficiencies of being difficult to handle and uneconomical to automate.
U.S. Pat. No. 4,636,024 discloses a wire positioning adapter for use in the plug connector of the type contemplated that positively holds the conductors in place. The adapter has a plurality of wire receiving holes formed in the adapter. The adapter is then deformed against the wires prior to insertion into a plug housing. This design does not lend itself to using wire on closely spaced centers because of the necessity of employing wire insertion holes to position the wires. In addition, there is no means of ensuring that the adapter is fully seated in the cavity formed in the housing such that the wire ends are properly positioned below the terminals.
In terminating shielded multi-conductor cable assemblies a conductive metal foil interposed between the bundle of discrete insulated conductors and the outer insulation jacket is electrically connected to a conductive shield on the plug housing. The plug shield in turn, is intended to mate with a conductive shield provided on a receptacle which is adapted to mateably receive the shielded plug assembly. This is typical of an input/output connector assembly used for the transmission of data. In such an application, it is necessary to provide a metal shield or shell around the plug housing which interconnects the cable foil with the receptacle ground.
It is desired that the metal shell be preassembled to the plug housing. In this manner, the customer does not have to worry about a loose part to apply correctly onto his assembly. In addition, it is desireable to have a one-piece shell for ease of handling and assembly at the factory. The round shaped configuration of multi-conductor shielded cable assemblies requires that the metal shell have a neck portion from which the unstripped portion of the cable assembly extends. The neck portion contacts the cable foil.
An example of a one-piece metal shell for an electrical connector is disclosed in U.S. Pat. No. 4,457,576. Unfortunately, however, the one-piece shield design illustrated in this patent cannot be used to provide the plug assembly with the metal shield or shell premounted.